(except that it would have to be written on one line). The default
value for the actions are normally what you want, and only need to be
changed in exceptional cases.

If the optional ! is placed before the status this means
the following action is used for all statuses but status itself.
I.e., ! is negation as in the C language (and others).

Before we explain the exception which makes this action item necessary
one more remark: obviously it makes no sense to add another action
item after the files service. Since there is no other service
following the action always is return.

Now, why is this [NOTFOUND=return] action useful? To understand
this we should know that the nisplus service is often
complete; i.e., if an entry is not available in the NIS+ tables it is
not available anywhere else. This is what is expressed by this action
item: it is useless to examine further services since they will not give
us a result.

The situation would be different if the NIS+ service is not available
because the machine is booting. In this case the return value of the
lookup function is not notfound but instead unavail. And
as you can see in the complete form above: in this situation the
db and files services are used. Neat, isn’t it? The
system administrator need not pay special care for the time the system
is not completely ready to work (while booting or shutdown or
network problems).